作者单位:Natl Inst Infect Dis, Dept Pathol, Shinjuku Ku, Tokyo 1628640, Japan[1]Univ Tokyo, Inst Med Sci, Int Res Ctr Infect Dis, Div Viral Infect,Dept Infect Dis Control,Minato K, Tokyo 1088639, Japan[2]Waseda Univ, Dept Life Sci & Med Biosci, Shinjuku Ku, Tokyo 1628480, Japan[3]